Rabbit manure organic fertilizer and preparation method thereof

Abstract

The invention provides a rabbit manure organic fertilizer and a preparation method thereof, and the rabbit manure organic fertilizer is prepared by using rabbit manure, rapeseed meal and wheat straw as raw materials through fermentation with a complex microbial inoculant; wherein the complex microbial inoculant is prepared by mixing a phanerochaete chrysosporium bacterial liquid, a bacillus subtilis bacterial liquid and a Thermus thermophilus bacterial liquid. Furthermore, the rabbit manure organic fertilizer is prepared by fermenting the complex microbial inoculant provided by the invention, the degradation of cellulose substances can be remarkably promoted, and the prepared fertilizer has a relatively high seed germination index when being used for germinating seeds. In addition, after fermentation, the content of copper and zinc in a water-soluble state and a weak acid extraction state in the raw materials is reduced, the risk that plants absorb heavy metals is reduced, and the application safety of the organic fertilizer is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of biomass fertilizers, and particularly relates to rabbit manure organic fertilizer and a preparation method thereof. Background Art

[0002] Rabbit manure is a major byproduct of rabbit farming, boasting advantages such as rich organic matter and a suitable pH level. Currently, the primary method for processing rabbit manure is aerobic composting, which generates high temperatures that effectively kill pathogens such as pathogens and parasite eggs in the manure. It also promotes the rapid decomposition of organic matter in the manure, gradually forming stable humus.

[0003] Currently, most patents related to rabbit manure composting involve the design of rabbit manure fermentation equipment or facilities, such as utility model patents CN 222182133 U, CN 222313030 U, and CN 219950858 U. These patents address the automation of rabbit manure aerobic composting from an engineering perspective, but fail to address the biological issue of rabbit manure composting efficiency. Invention patent CN 108033854 A discloses a method for producing bio-organic fertilizer using rabbit manure. While data on increased yields is mentioned, data on the nutritional profile of the fermented material before and after fermentation, as well as the safety of heavy metal forms for plants and soil, is lacking.

[0004] Rabbits are herbivores, and their digestive systems, feed composition, and excretion characteristics differ from those of pigs and chickens. This results in higher levels of cellulose, hemicellulose, and lignin in rabbit manure. The degradation of cellulose and lignin during rabbit manure composting takes longer, limiting the composting efficiency. Furthermore, analysis has revealed that rabbit manure contains a significant amount of heavy metals. If not thoroughly composted, long-term application of rabbit manure to soil may negatively impact soil quality. Summary of the Invention

[0005] In view of this, the present invention provides a rabbit manure organic fertilizer which has high degradation rates of cellulose, hemicellulose and lignin and converts heavy metals into a form that is not easily absorbed by plants, and a preparation method thereof.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: A rabbit manure organic fertilizer, which is prepared by fermenting rabbit manure, rapeseed meal and wheat straw with a composite bacterial agent; The composite bacterial agent is prepared by mixing the bacterial liquid of Phanerochaete chrysosporium, the bacterial liquid of Bacillus subtilis and the bacterial liquid of Thermus thermophilus.

[0007] Furthermore, the mass ratio of the rabbit manure, rapeseed meal, and wheat straw is (22-28): (1.5-2.5): (2.5-3.5).

[0008] In some specific embodiments, preferably, the mass ratio of the rabbit manure, rapeseed meal, and wheat straw is 25:2:3.

[0009] Furthermore, the volume ratio of the bacterial solution of Phanerochaete chrysosporium, the bacterial solution of Bacillus subtilis and the bacterial solution of Thermus thermophilus in the composite bacterial agent is 1:(0.5-2):(0.5-2); Among them, the OD values ​​of Phanerochaete chrysosporium, Bacillus subtilis and Thermus thermophilus were 600 The values ​​are all between 0.6 and 0.8.

[0010] In some specific embodiments, preferably, the volume ratio of the Phanerochaete chrysosporium bacterial solution, the Bacillus subtilis bacterial solution and the Thermus thermophilus bacterial solution in the composite bacterial agent is 1:2:2; Among them, the OD values ​​of Phanerochaete chrysosporium, Bacillus subtilis and Thermus thermophilus were 600 The values ​​are all 0.7.

[0011] Furthermore, the mass of the composite bacterial agent is 1% to 1.5% of the total mass of rabbit manure, rapeseed meal and wheat straw.

[0012] A method for preparing the above-mentioned rabbit manure organic fertilizer comprises the following steps: S1. Phanerochaete chrysosporium, Bacillus subtilis, and Thermus thermophilus were inoculated into culture medium to prepare bacterial solutions, and then the three bacterial solutions were mixed to obtain a composite bacterial agent; S2. Crush and sieve the wheat straw, then add rabbit manure and rapeseed meal, mix well, and obtain compost raw material; S3. Add the prepared composite bacterial agent to the compost raw materials, mix well, and ferment to obtain rabbit manure organic fertilizer.

[0013] Furthermore, the culture medium for culturing Phanerochaete chrysosporium in step S1 is PDA culture medium; The culture medium for culturing Bacillus subtilis is beef extract peptone medium; The culture medium for culturing Thermus thermophilus contains the following components by mass percentage based on 1 L of distilled water: 1% lactose, 1% hydrolyzed casein, and 1% MgCl2·6H2O.

[0014] Furthermore, in step S2, the moisture content of the compost raw material is controlled to be 45% to 55%.

[0015] Furthermore, the fermentation time is 30 to 40 days, and the fermented material is turned over every 2 to 4 days during the fermentation period.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This application selects Phanerochaete chrysosporium, Bacillus subtilis and Thermus thermophilus as fermentation bacteria, and obtains a composite bacterial agent with high enzyme activity (25.3 U / mL) through reasonable configuration; further, the composite bacterial agent provided in this application is used to ferment and prepare rabbit manure organic fertilizer, which can significantly improve the degradation of cellulose substances (relative degradation rate reaches 34.81%); using the prepared fertilizer for germinating seeds can obtain a higher seed germination index (111.7%, far higher than the NY / T 525-2021 organic fertilizer standard requirements).

[0017] Furthermore, fermentation reduces the water-soluble and weakly acid-extractable copper and zinc contents in the raw materials, reducing plant absorption of heavy metals and minimizing soil damage. Water-soluble copper concentrations are as low as 3.17 mg / kg, and weakly acid-extractable copper concentrations are as low as 2.28 mg / kg; water-soluble zinc concentrations are as low as 16.45 mg / kg, and weakly acid-extractable zinc concentrations are as low as 19.56 mg / kg. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 OD values ​​of different composite strains after inoculation into sodium carboxymethyl cellulose medium in Example 1 of the present invention 600 Changes.

[0019] Figure 2 The temperature changes of the raw material pile before and after adding the composite bacterial agent in Example 2 of the present invention.

[0020] Figure 3 This is the change in the seed germination index of the compost raw material before and after adding the composite bacterial agent in Example 2 of the present invention.

[0021] Figure 4 This is the change in seed germination index of organic fertilizers prepared with different composite bacterial agents in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0022] The present invention will be further described in detail below in conjunction with specific examples so that those skilled in the art can more clearly understand the present invention. Unless otherwise specified, the technical means used in the following examples are conventional means well known to those skilled in the art, and all reagents and consumables are commercially available products.

[0023] Example 1 This embodiment provides a method for preparing a composite bacterial agent in rabbit manure organic fertilizer, comprising the following steps: 1.1 Preparation of bacterial suspension Phanerochaete chrysosporium (strain purchased from Beina Biotechnology, strain number BNCC 190652) was inoculated into potato culture medium (PDA) and cultured at 37°C and 150 rpm with shaking (several small glass beads were added to prevent bacterial flocculation) for expansion. Bacillus subtilis (purchased from Wuhan University Microbiology Collection Center, strain number CCTCC AB 130008) was inoculated into beef extract peptone medium and cultured at 37°C and 180 rpm with shaking for expansion. Thermus thermophilus (purchased from Beina Biotechnology, strain number BNCC 186418) was inoculated into the optimized culture medium and cultured in a constant temperature water bath shaker at 75°C and 180 rpm for expansion.

[0024] The three bacteria were cultured for 48 h and then centrifuged to collect the cells. OD values ​​were then calculated using PBS solution and the cells. 600 It is a bacterial suspension of 0.7.

[0025] The PDA medium consists of the following: 200g peeled potatoes, cut into small pieces, placed in a pot, add 1000mL of distilled water, and boil for 20-30 minutes. Filter the potato residue through gauze, add 20g of glucose to the filtrate, and dilute to 1000mL. The composition of beef extract peptone medium is as follows: beef extract 3 g / L, peptone 10 g / L, NaCl 5 g / L, and the pH value is adjusted to 7.4-7.6; The optimized culture medium composition contains the following mass percentage components based on 1 L of distilled water: 1% lactose, 1% hydrolyzed casein, and 1% MgCl2·6H2O.

[0026] 1.2 Optimal volume ratio of bacterial liquid In order to determine the optimal volume ratio of the three bacterial solutions, the following experiments were conducted: The three bacterial solutions were mixed according to different volume ratios (see Table 1 for volume ratios) and inoculated into sodium carboxymethyl cellulose medium for cultivation. After 39 h of cultivation, the cellulase activity of the supernatant was determined (using the DNS method, see Table 2 for results). At the same time, the OD value of the composite strains was determined. 600 Changes (see the results Figure 1 ).

[0027] The components of sodium carboxymethyl cellulose medium are as follows: sodium carboxymethyl cellulose (CMC-Na) 5 g / L, (NH4)2SO4 2 g / L, yeast extract 0.5 g / L, KH2PO4 1 g / L, NaNO3 1 g / L, MgSO4·7H2O 0.5 g / L, NaCl 0.5 g / L, peptone 0.5 g / L, pH = 7.0.

[0028] Table 1 Details of the volume ratio of the three bacterial solutions

[0029] Table 2 Specific enzyme activity data of each experimental group

[0030] From Tables 1, 2 and Figure 1 The results showed that the final enzyme activity of the three bacteria, when mixed at different volume ratios, ranged from 19.6 to 25.3 U / mL. Specifically, when the volume ratio of Phanerochaete chrysosporium:Bacillus subtilis:Thermus thermophilus was 1:2:2, the composite inoculum rapidly grew in a culture medium containing sodium carboxymethylcellulose as the carbon source, and produced the highest CMCase activity (25.3 U / mL). Therefore, this ratio was selected as the optimal ratio for subsequent fermentation.

[0031] Example 2 This embodiment provides a method for preparing rabbit manure organic fertilizer based on the optimal composite bacterial agent in Example 1, comprising the following steps: First, wheat straw was crushed and sieved. Then, rabbit manure, rapeseed meal, and wheat straw were mixed uniformly in a mass ratio of 25:2:3 to create the compost. Measurements showed that the carbon-nitrogen ratio in the compost was approximately 24, and the moisture content was approximately 50%. The basic physical and chemical properties of each raw material are shown in Table 3.

[0032] Table 3 Basic physical and chemical properties of each raw material

[0033] Then, the best composite bacterial agent in Example 1 was added to the compost raw material at a rate of 1.5% by mass of the compost raw material, mixed evenly, and fermented. After fermentation, rabbit manure organic fertilizer was obtained. The fermentation time was 30 to 40 days, and the fermented material was turned every 2 to 4 days during the fermentation period.

[0034] Finally, a control group of compost without compound bacteria was set up to compare the temperature changes of the raw material pile before and after adding the compound bacteria (see the results). Figure 2 ), the effect of compost on seed germination index before and after fermentation (see Figure 3 ). The content of different forms of copper and zinc in compost raw materials before and after fermentation (results are shown in Table 4), Among them, the determination method of the content of different forms of copper and zinc refers to the "Sequential Extraction Procedure for 13 Trace Elements in Soil and Sediment" (GB / T 25282-2010).

[0035] The method for determining the seed germination index (GI) refers to the method described in Appendix F of "Organic Fertilizer" (NY / T 525-2021).

[0036] Depend on Figure 2 It can be seen that the temperature of the compost raw materials increased faster after the compound bacterial agent was added in the early stage (3-5 days), indicating that the increase in the number of microorganisms promoted the decomposition of organic matter in the material, resulting in a faster increase in the temperature of the pile.

[0037] Depend on Figure 3 It can be seen that when the GI ≥ 50%, the compost product has minimal toxicity to crop growth, and when the GI ≥ 80%, the toxicity to crop growth is almost zero. On the last day of composting, the GI of both the control and the inoculant-added groups was greater than 80%, indicating that both groups had reached maturity. Furthermore, the GI of the inoculant-added group was significantly higher than that of the control group (P < 0.05), indicating that the compound inoculant promotes composting efficiency.

[0038] Table 4 Contents of different forms of copper and zinc in the compost products of the composite microbial agent group and the control group

[0039] As shown in Table 4, the water-soluble and weakly acid-extractable copper and zinc contents in the compost product decreased after the addition of the composite bacterial agent. These two forms of heavy metals are easily absorbed and utilized by plants. This shows that the addition of bacterial agents can improve the safety of fertilizer application.

[0040] Comparative Example 1 This comparative example provides composite bacterial agents formed by other bacterial liquid combinations to explore the effects of different composite bacterial agents on fermentation, including the following steps: This comparative example sets up two other composite bacterial agents for comparison with the best composite bacterial agent formula in Example 1 of this application. The specific composite bacterial agent formulas are as follows: Combination 1: the best composite bacterial agent formula in Example 1; Combination 2: yeast culture liquid: Bacillus subtilis culture liquid: lactic acid bacteria culture liquid = 1:2:2; Combination 3: Lactic acid bacteria liquid: Bacillus subtilis liquid: yeast liquid = 1:2:2.

[0041] Control group: fermentation without adding bacterial agents.

[0042] Among them, the OD of each bacterial solution 600 Both are 0.7, and the ratios are also volume ratios.

[0043] The three composite bacterial agents were inoculated into straw fermentation medium (10 g of crushed and sieved straw, 5 g of peptone, 0.4 g of MgSO4·7H2O, 2.0 g of KH2PO4, 5.0 g of yeast powder, 10.0 g of NaCl, 1 L of distilled water; pH = 6.0) in equal amounts at a 2% inoculum rate. The culture was continued for 15 days, and the relative degradation rate of the straw was calculated (the results are shown in Table 5).

[0044] Among them, relative degradation rate (%) = (dry weight of control straw residue - dry weight of straw residue after bacterial degradation) / dry weight of control straw residue × 100%.

[0045] Table 5 Relative degradation rates of three different composite bacterial agents

[0046] From Table 5 we can see that: at the same OD 600 Under the same value and volume ratio, the relative degradation rate of the composite bacterial agent provided in this application for straw is significantly higher.

[0047] Furthermore, in order to understand the specific fermentation situation in the compost raw material, the rabbit manure organic fertilizer was prepared by the same method as in Example 2 in combination 2 and 3, and the fermentation results were compared and measured; wherein, the seed germination index is shown in FIG. Figure 4 .

[0048] Depend on Figure 4 It can be seen that when composting was carried out according to Combination 2 and Combination 3, the seed germination index of the fertilizer did not increase significantly compared with the control group at 42 days, and the germination index only reached 76.3% and 72.7%, which was much lower than the composting result of Combination 1 (111.7%).

[0049] Analysis of various experimental data indicates that this application, through the selection of specific bacterial species and their rational configuration, has produced a composite bacterial agent with high enzyme activity. Furthermore, using the composite bacterial agent provided in this application to ferment rabbit manure to produce organic fertilizer significantly promotes the degradation of cellulose, resulting in a high germination index for seed germination. Furthermore, fermentation reduces the water-soluble and weakly acid-extractable copper and zinc content in the raw material, reducing the risk of heavy metal absorption by plants and improving the safety of organic fertilizer application.

[0050] The raw materials not specifically described in the present invention are all existing materials that can be directly purchased from the market.

[0051] The above is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A rabbit manure organic fertilizer, characterized in that: The rabbit manure organic fertilizer is prepared by fermenting rabbit manure, rapeseed meal and wheat straw with a composite bacterial agent; The composite bacterial agent is prepared by mixing the bacterial liquid of Phanerochaete chrysosporium, the bacterial liquid of Bacillus subtilis and the bacterial liquid of Thermus thermophilus.

2. Rabbit manure organic fertilizer according to claim 1, is characterized in that, The mass ratio of the rabbit manure, rapeseed meal and wheat straw is (22-28): (1.5-2.5): (2.5-3.5).

3. Rabbit manure organic fertilizer according to claim 1, is characterized in that, The mass ratio of the rabbit manure, rapeseed meal and wheat straw is 25:2:

3.

4. Rabbit manure organic fertilizer according to claim 1, is characterized in that, The volume ratio of the Phanerochaete chrysosporium solution, the Bacillus subtilis solution and the Thermus thermophilus solution in the composite bacterial agent is 1: (0.5-2): (0.5-2); Among them, the OD values ​​of Phanerochaete chrysosporium, Bacillus subtilis and Thermus thermophilus were 600 The values ​​are all between 0.6 and 0.

8.

5. Rabbit manure organic fertilizer according to claim 4, is characterized in that, The volume ratio of the bacterial solution of Phanerochaete chrysosporium, the bacterial solution of Bacillus subtilis and the bacterial solution of Thermus thermophilus in the composite bacterial agent is 1:2:2; Among them, the OD values ​​of Phanerochaete chrysosporium, Bacillus subtilis and Thermus thermophilus were 600 The values ​​are all 0.

7.

6. The rabbit manure organic fertilizer according to claim 1, wherein The mass of the composite bacterial agent is 1% to 1.5% of the total mass of rabbit manure, rapeseed meal and wheat straw.

7. A method for preparing rabbit manure organic fertilizer according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Phanerochaete chrysosporium, Bacillus subtilis, and Thermus thermophilus were inoculated into culture medium to prepare bacterial solutions, and then the three bacterial solutions were mixed to obtain a composite bacterial agent; S2. Crush and sieve the wheat straw, then add rabbit manure and rapeseed meal, mix well, and obtain compost raw material; S3. Add the prepared composite bacterial agent to the compost raw materials, mix well, and ferment to obtain rabbit manure organic fertilizer.

8. The preparation method according to claim 7, characterized in that The culture medium for culturing Phanerochaete chrysosporium in step S1 is PDA culture medium; The culture medium for culturing Bacillus subtilis is beef extract peptone medium; The culture medium for culturing Thermus thermophilus contains the following components by mass percentage based on 1 L of distilled water: 1% lactose, 1% hydrolyzed casein, and 1% MgCl2·6H2O.

9. The preparation method according to claim 7, characterized in that In step S2, the moisture content of the compost raw material is controlled to be 45% to 55%.

10. The preparation method according to claim 7, characterized in that The fermentation time is 30~40 days, and the fermented material is turned over every 2~4 days during the fermentation period.

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